In general, a multi-layer thin film interconnect structure is fabricated directly onto an electrically-good substrate, e.g., a ceramic or glass-ceramic substrate. Such a fabrication process has several drawbacks including WIP (work in progress) concerns because of the serial nature of the manufacturing sequence, and undesirable processing/handling of highly-valued glass-ceramic substrates. Further, if the fabricated multi-layer thin film structure is defective, then an otherwise electrically-good glass-ceramic substrate must be discarded or reworked.
Processing schemes have been proposed which allow for interconnect and other structures to be fabricated separately from the module on which they ultimately will be employed. The following are examples of such processing schemes.
U.S. Pat. No. 4,743,568 to Wood discloses a method in which an oxidation layer is formed on a silicon wafer. This is followed by the deposition of several metal and polyimide layers which are patterned to form a desired multilevel interconnect structure. This interconnect structure is subsequently separated from the silicon wafer by etching away the oxidation layer.
In U.S. Pat. No. 4,348,253 to Subbarao et al an adhesive layer is formed on a plating block, and a semiconductor wafer is provided on the adhesive layer. The adhesive layer is used for temporarily adhering the substrate wafer to the plating block. Specifically, after the semiconductor wafer is subjected to a plating process, the adhesive layer is dissolved in a solvent, and the plated semiconductor wafer is removed from the plating block.
U.S. Pat. No. 4,774,194 to Hokuyou discloses a process for manufacturing a solar cell structure. The process includes forming a "removable layer" on a semiconductor substrate, and fabricating the solar cell structure on the removable layer. The removable layer is then etched away to separate the fabricated solar cell structure from the semiconductor substrate.
U.S. Pat. No. 4,448,636 to Baber discloses a method in which a uniform metal film is applied over a patterned resist layer. A short pulse of radiant energy is then applied to the metal film, thereby causing the resist layer underneath the metal film to be locally heated. As a result, outgassing occurs which breaks the mechanical bond between the metal film and the patterned resist. The metal film can then be removed from the resist.